Rotary compressor



Feb. 25, 195s 'Filed oct. 26, 1955 H. C. OSTERKAMP ROTARY COMPRESSOR 2Sheets-Sheet 1 Feb. 25, 1958 f H. c. osTERKAMP 2,824,687

ROTARY COMPRESSOR Filed oct. 26, 1955 Y 2 sheets-sheet 2 ATTORNEYS v Y.

United States lPatent "f- ROTARY COMPRESSOR Henry C. Osterkamp, ElmGrove, Wis., assignor to Westinghouse Air Brake Company, Wilmerding,Pa., a corporation of Pennsylvania Application October 26, V1955, SerialNo. 542,832

4 Claims. (Cl. 230-158) The present invention relates generally toimprovements in the art of compressing air or the like, and relates moreparticularly to improvements in the construction and operation ofmulti-stage rotary air compressors of the sliding vane type.

A primary object of my present invention is to provide an improvedmulti-stage rotary compressor wherein the low and high pressure rotorsare disposed in axial alinement with the low and high pressure chambersbeing formed by a simple partition plate disposed and sealingly retainedwithin the bore of a common main cylinder.

Another specic object of my present invention is to provide an improvedmulti-stage rotary compressor of the sliding vane type in which a singleunitary cylinder houses both the low and the high pressure rotors whichoperate in separate chambers segregated and sealed from each other by areadily removable partition.

Still another specific object of the present invention is to provide animproved multi-stage rotary compressor wherein all of the parts arereadily accessible merely upon removal of the end head of the cylinderand axial withdrawal of the low and high pressure rotor assembly.

A further specific object of the present invention is to provide animproved rotary compressor assemblage which comprises essentially asingle unitary cylinder having a common bore of uniform diameter closedon opposite ends by removable end heads,.a single unitary shaftextending eccentrically through the bore and journalled for rotation inthe end heads, low and high pressure rotors mounted on the shaft forrotation therewith and each having radially extending sliding vanescooperable with the wall of the bore, a partition plate disposed betweenthe rotors and peripherally sealed within the cylinder bore to form lowand high pressure chambers, means forming an air communicationpassageway between the low and the high pressure chambers, and alubricant pump housed entirely within one of the end heads and driven bythe unitary rotor shaft.

These and other specific objects and advantages of the invention willbecome apparent from the following detailed description.

A clear conception of the features constituting the presentimprovements, and of the mode of constructing and operating a typicalrotary compressor embodying the invention, may be had by referring tothe drawings accompanying and forming a part of this specication whereinlike reference characters designate the same or similar parts in thevarious views.

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Fig. 1 is a longitudinal section through a typical multi-vK stage rotarysliding vane type compressor embodying the invention, the section havingbeen taken along the irregular line 1-1 of Fig. 2;

Fig. 2 is a transverse section through the compressor taken along theirregular line 2 2 of Fig. l; and

Fig. 3 is a somewhat enlarged fragmentary longitudinal section through aportion of the unit taken along the irregular line 3 3 of Fig. 2.

While the several features of the present invention have been shown anddescribed herein as being embodied in a compressor of the rotary slidingvane type having two compression stages and being especially applicablefor direct connection withan engine flywheel, it is not intended tounnecessarily limit or restrict the invention and its application or'use by reason of such limited ern-y bodirnents, since the same featurescould of course bez utilized to advantage in rotary compressors of morethan two stages and adapted to be coupled in any suitable man'- ner witha suitable driving source.- It is also contemplated that certainspecific descriptive terms utilized here-` in shall be given thebroadest possible interpretation consistent with the disclosure.

Referring to the drawings, the improved assemblage disclosed therein asillustrating the embodiments of the invention comprises, in general, asingle' unitary cylinder S having a single bore 6 of uniform diameterextending longitudinally therethrough, a pair of end heads 7, 8removably secured to the opposite ends of the cylinder 5 as by means ofbolts 9, iii respectively to thereby clos'eV the opposite ends of thebore 6, the end head 8 preferably' being provided with an outwardly openrecess 11 therein for purposes hereinafter more fully set forth, asingle unitary shaft l2 extending eccentrically through the bore 6 andjournalled for rotation in the end heads 7, 8, the shaft 12 having oneend extending iritoV the recess l and having the other end thereofsuitably' coupled as by means of splining 13 to a driving source such asthe flywheel 14 carried by the crank shaft l5 of anvengine or motor, lowand high pressure rotors 16, 17 respectively carried by the shaft l2 forrotation therewith, each of the rotors 16, 17 having the usual series ofradially extending sliding varies or blades i8, 19 respectivelycooperable with the wall of the bore 6, a partition wall or plate 22disposed loosely on the shaft 12 between the rotors 16, 117 andperipherally coacting with the wall of the bore` 6 to thereby'fcrm lowand high pressure chambers 20, 21'respectively therein, the partition 22preferably being se# cured in position within thebore das by means of aseries of machine screws 29 or the like, means forming an aircommunication passageway 23, 24 between the low and high pressurechambers, the air communication passageway 23, 24 preferably beingformed directly in the cylin' der 5 and extending outwardly around thebore 6 therein, means such as a pair of cooperating rotors 25, 26 housedwithin the recess lli of the end heads 8V and providing alubricant pump,the rotor 25 of the pump'being mounted on and driven by the endl of theshaft 12, and a cover 27 for the recess 1l removably secured to the endhead 8 as by means of bolts 28 to protectively confine the pump withinthe recess 11.

The end head 7 may be conveniently formed in the rotor 16 may, ifdesired, be formed integral with the shaft 12 as by casting the same ofone piece, or it may be rigidly secured to the shaft 12 in any suitablemanner as by means of a key or the like, the high pressure rotor alsobeing secured to the shaft 12 for rotation therewith in any suitablemanner as by a key 34. The partition 22 should loosely surround theshaft 12 so as to permit free rotation of the shaft relative ,to thepartition, and the periphery of the partition 22 should preferably besealed about the wall of the bore 6 as by means of suitable O-ring seals35 retained in suitable annular grooves 36 in the wall of the bore 6.

Suitable bearings 37, 38 may furthermore be provided in the end heads 7,8 respectively for facilitating rotation of the shaft 12, and gasketsmay, of course, be provided wherever necessary to minimize leakage andloss of air. The cylinder may be cast or otherwise formed in one piecewith integral walls 39, 40, 41, 42 being provided in the casting forforming the air passageways, one side of the cylinder being preferablyclosed as by a suitable cover plate 43 having an inlet opening 44 forsupplying air to the low pressure chamber through suitable ports 45 andanother side of the cylinder 5 being closed as by a suitable removablecover plate 46 having a discharge or outlet opening 47 therein fordischarging air from the high pressure chamber 21 through suitable ports48. Accordingly, the walls 39, 40 cooperate with the cover plate 43 toform the low pressure air inlet chamber 49, the walls 39, 42 cooperatewith the cover plate 46 to form the low pressure discharge chamber andpassageway 23 which receives the initially compressed air from the lowpressure chamber 20 through suitable ports 50 and conducts the initiallycompressed air around a side of the cylinder beyond the bore 6 to thehigh pressure inlet chamber 24 formed by the walls 40, 41, the initiallycompressed air being then conducted through suitable intake ports 51 tothe high pressure chamber 21 and then through the ports 48 to the outlet47.

The pump formed by the rotors 25, 26 working in the recess 11 formed inthe end head 8 may be of the usual gear type, with the rotor beingsecured to the end of the shaft 12 as by means of a key 53 and the rotor26 may be freely rotatable on a stub shaft 54 or the like. The inlet ofthe lubricant pump formed by the rotors 25, 26 may communicate in theusual manner with a source of lubricant supply and the lubricantdischarged by the pump may be conducted in a usual manner throughsuitable conduits or passageways 55, 56, 57 formed in the end head 8, awall of the cylinder 5, and the end head 7 respectively. From theconduit 56 lubricant is supplied through a branch or branches 58 to thehigh pressure chamber 21, while lubricant is also supplied to the lowpressure chamber 20 from the conduit 56 by means of one or more branches59, the conduit 57 in turn supplying lubricant to the bearing 37 withthe lubricant escaping from around the bearing 37 to the recess 31 inthe end head 7 and being drawn back to the low pressure chamber 20 as bymeans of a conduit 60. The lubrication system as such is, however, oldin the art and does not form a part of this invention except for thepump construction and the manner in which itis recessed and housedseparately within the end head 8.

In operation, the shaft 12 is rotated in the direction of the arrow inFig. 2 by means of the engine through the iiywheel 14. The shaft 12carries with it the low and high pressure rotors 16, 17, and air to becompressed is drawn in through the inlet 44 into the chamber 49 and thenthrough the ducts 45 into the low pressure chamber `20 as also indicatedby the arrows. The vanes 18 act to compress the air entering the chamber20 as the low pressure rotor revolves, and the initially compressed airis forced through the ducts 50 into the chamber 23 and then through apassageway formed in the cylinder outside of the bore 6 in the directionof the arrows to the chamber 24. From the chamber 24 the initiallycompressed air `is drawn through the ducts or ports 51 into the highpressure chamber 21 and is further compressed by the revolving blades 19carried by the rotor 17, the finally compressed air being dischargedthrough the ports 48 and outlet 47, and to add flexibility to the unit,an alternate outlet 61 may be provided in another wall of the cylinderas shown in Fig. 2. As the air is thus compressed, the lubricant pumpalso forces oil or other lubricant in the direction of the arrows inFig. 3 through the several conduits to aord lubrication of thecompressor.

From the foregoing detailed description, it is believed apparent thatthe present invention contemplates the provision of a multistage rotarycompressor of the sliding vane type possessing extreme simplicity andwhich may be readily constructed at exceedingly low cost. The improvedunit is composed of relatively few parts, all of which are readilyaccessible for inspection, replacement and/or repair. Access to the highpressure rotor 17 and its vanes 19, may, of course, be readily attainedby merely removing the end head 8 in an obvious manner without in anyway disturbing the lubricant pump confined within the recess 11, and byremoving the machine screws 29, the shaft 12, rotors 16, 17 andpartition 22 may be axially removed as a unit, if desired, for access toall of the parts excluding the lubricant pump. On the other hand, accessmay be attained separately only to the lubricant pump, if desired, byremoval of the cover plate 27 in an obvious manner, and access to thevarious air passageways and ports may be attained through removal ofeither or both of the cover plates 43, 46, both of which may likewise besecured to the cylinder as by means of bolts 62, 63. All parts of theassemblage may be manufactured and machined in an expedient manner, andthese parts may obviously be quickly and easily assembled. While thepartition 22 has been shown for purposes of illustration as looselysurrounding the shaft 12, it may be desirable to provide a bearingembracing the shaft within the bore of the partition, in which case asuitable branch lubricant line may be run to the bearing from the line56. Also, the seals 35 might be entirely eliminated or any suitablenumber may be provided, and it may or may not be necessary or desirableto secure the partition in position by means of the screws 29. Thebearings 37 may likewise be of any suitable type such as ball or rollerbearings, and it is believed apparent that the conduit or branchlubricant line should lead into the chamber 20 on the suction side ofthe rotor. Furthermore, although the lubricant pump has been shown anddescribed as being housed within the recess 11 of the end head 8, it mayadvantageously be housed within a recess provided for such purpose inthe removable plate or cover 27.

.lt lshould be understood that it is not desired to limit this inventionto the exact details of construction or to thepreclse mode of use hereinshown and described, since various modifications within the scope of theappended claims may occur to persons skilled in the art to which thisinvention pertains.

I claim:

l. A rotary compressor comprising, a unitary generally cylindricalcasing having a single bore of uniform diameter extending therethrough,end heads removably secured to each end of said casing to close theopposite ends of said bore, one of said end heads having an outwardlyopen recess therein, a single unitary shaft extending eccentricallythrough said bore and journalled for rotation in said end heads, low andhigh pressure rotors carried by said shaft for rotation therewith andeach having radially extending sliding vanes cooperable with the wall ofsaid bore, a partition disposed between said rotors and peripherallyseated on the wall of said bore to form low and high pressure chamberstherein, means forming an air communication passageway between said lowand high pressure chambers, a lubricant pump housed entirely within saidend head recess and driven directly by said shaft, and a flat removablecover plate for said recess to contine said pump therein.

2. A rotary compressor comprising, a unitary generally cylindricalcasing having a single bore of uniform diameter extending therethrough,end heads removably secured to each end of said casing to close theopposite ends of said bore, one of said end heads having an outwardlyopen recess therein, a single unitary shaft journalled for rotation insaid end heads and extending eccentrically through said bore and intosaid recess, a stub shaft extending from said one end head into saidrecess laterally of said eccentric shaft, low and high pressure rotorscarried by said eccentric shaft for rotation therewith and each havingradially extending sliding vanes cooperable with the wall of said bore,a partition disposed between said rotors and peripherally seated on thewall of said bore to form low and high pressure chambers therein, an aircommunication passageway between said low and high pressure chambersformed in said casing out wardly beyond said bore, a lubricant pumphoused entirely Within said end head recess and comprising a pair ofcooperating rotors, one of which is driven directly by said eccentricshaft and the other of which is carried by said stub shaft, and a atremovable cover plate for said recess to confine said pump therein.

3. A rotary compressor comprising, a unitary casing having an integralcylindrical portion provided with a single bore of uniform diameterextending therethrough, end heads removably secured to each end of saidcasing to close the opposite ends of said bore, a single unitary shaftextending eccentrically through said bore and journalled for rotation insaid end heads, low and high pressure rotors carried by said shaft forrotation therewith and each having radially extending sliding vanescooperable with the Wall of said bore, a partition disposed between saidrotors and peripherally sealed against the Wall of said bore to form lowand high pressure chambers therein, an air communication passagewaybetween said low and high pressure chambers formed directly in saidcasing outwardly beyond said bore, a cover removably secured to one sideof said casing and having an air inlet communicating with said lowpressure chamber, and another cover removably secured to another side ofsaid casing and having an air outlet communicating with said highpressure chamber.

4. A rotary compressor comprising, a unitary casing having an integralcylindrical portion provided with a single bore of uniform diameterextending therethrough, end heads removably secured to each end of saidcasing to close the opposite ends of said bore, a single unitary shaftextending eccentrically through said bore and journalled for rotation insaid end heads, low and high pressure rotors carried by said shaft forrotation there- With and each having radially extending sliding vanescooperable with the wall of said bore, a partition disposed on saidshaft between said rotors and peripherally sealed against the wall ofsaid bore to form low and high pressure chambers therein, exteriorlyaccessible removable means for positively preventing displacement ofsaid partition Within said bore while permitting axial withdrawal ofsaid shaft, said low and high pressure rotors and said partition as aunit upon removal of said means and one of said end heads, and meansforming an air communication passageway between said 10W and highpressure chambers.

References Cited in the tile of this patent UNITED STATES PATENTS1,054,574 Leutz Feb. 25, 1913 2,215,256 Stoltz Sept. 17, 1940 FOREIGNPATENTS 149,323 Australia Dec. 5, 1952 660,528 France Feb. 19, 19291,025,278 France Jan. 21, 1953

